The European Commission’s hardline Brexit negotiator has reasserted that the UK cannot “have autonomy anymore” over its trade policy if it remains tied to the bloc’s Customs Union.

Theresa May has hinted she could explore a “partial” customs union with the bloc, and Labour’s shadow Brexit minister Sir Keir Starmer has claimed the UK can retain membership with a degree of control over trade.

“When you’re in a customs union for goods, like Turkey for example, you become part of a common trade policy – you don’t have autonomy anymore,” he added.

Reports last week suggested the European Union (EU) was ready to offer Britain a better deal than the one it gave Turkey – which is inside the Customs Union but not a member state of the EU – raising the hopes of those pushing for a “soft” Brexit.

The claim was followed by reports over the weekend that suggested Prime Minister Theresa May was ready to cave to demands for continued customs ties, with one of her advisers suggesting the outcome would not upset her.

A spokesman for Mrs. May denied the reports and insisted she would stick to her manifesto pledge to break from the union.

The Customs Union has become the focus of anti-Brexit campaigning in Parliament in recent weeks.

The previous week, on the 19th of March, the House of Lords voted by a strong majority to retain Customs Union links, followed by a group of MPs, including senior Tories, pushing for a debate on the topic in the Commons.

However, this Thursday, a leading member of the Eurosceptic European Research Group headed by Jacob Rees-Mogg MP, threatened Mrs. May with a rebellion and a vote of no confidence if she capitulated on the issue.

Mr. Rees-Mogg has also said she must not back down, and leading members of the Cabinet, including foreign secretary Boris Jhonson and environment secretary Michale Gove, are pushing for the UK to leave.